Process of producing electrolytic copper



Dec. 22 1925.

F. L. ANTISELL PROCESS OF PRODUCING ELECTROLYTIC COPPER Filed Jan. 11, 1922 INVENTOR Fran/t L. Anf/sex/ BY A. ATTOR Patented Dec. 2 2, 1925.

UNITED :STA

FRANK LINDEN ANTISELL, OF PERTH AMBOY, NEW JERSEY.

PROCESS OF PRODUCING ELECTROLYTIC COPPER.

Application filed January 11, 1922. Serial No.'628,428.

To whom it may] concern:

Be it known that I, FRANK LINDEN AN- 'lISELL, a citizen of the United States, and-a resident of Perth Amboy, county of Middlesex, State of New Jersey, have invented,

certain new and useful Improvements in Processes of Producing Electrolytic Copper, of which the following is a specification.

My invention concerns the electrodeposition of copper-from aqueous solutions and it has for its object an improved process for conducting the electrolysis, whereby the copper deposited upon the cathode is. of a quality superior to that obtained heretofore, having a greater copper content and a reduced quantity of impurities.

In carrying out the electrolysis of copper sulphate solutions as usually practiced in the copper refining industry, it is customary to employ an electrolyte which contains approximately three per cent copper and twelve per cent free sulfric acid. In addition to the copper and acid such a solution as used in practice contains also a certain percentage of impurities, such as iron, alumina,

selenium, etc.

Solutions of the above composition have been found to be the most satisfactory in View of the electric current carrying capacity of the copper ion and of the sulfuric acid ion or (sulphron SO During the electrolysis the SO, ion dissolves copper at the anode, while at the same time the copper ion is deposited at the cathode. As the electrolysis proceeds, there results an imoverished film of electrolyte on the surface of each of the electrodes. The amount and thickness of the said impoverished film depends upon various conditions, such as the composition of the electrolyte, the temperature of the solution, the impurities contained therein, the amount of current pass ing through the electrolyte, the surface tension of the'electrodes, and other factors.

With very low current densities the concentration of'the positive and negative ions at the surfaceof the electrodes is low, and therefore. the migration of the copper ions and the sulfuric (S0,) ion to their res ective electrodes can continue, only slig tly undisturbed. However, even at 'low current densities a tendency to polarization develops at the cathode, which precludes the posslbility'of producing dense deposits'of.

which are practically reasonable.

deposited thereon.

cycle, the amount 0 copperwhen current densities are used As the current density is-increased, the film of impoverished electrolyte at the cathode becomes greater, owing to the fact that the copper is removed at a great ratio, while the above mentioned impurities and copper which are present in the solution act as a concentration diaphragm which interferes with the rapid transfer of the sulfuric (S0 ion to the anode.' This phenomenon, in addition to the surface tension of the cathode, results in a film of impoverished electrolyte which is considerably greater at the lower edge of the cathode than at the top. As the result of'this change in the e1ectrolyte, drogen sulfid liberated and amorphous cop'-' perand hydrogen are set free at the cathode and incorporated with the metallic copper The copper deposited under such conditions, while of relatively high purity, is mechanically in a strained condition, which-condition manifests itself in the appearance of twinned crystals. In addition it also contains amorphous copper and-hydrogen.

I have found that copper deposits havfree hydrogen is generated and hying improved physical and metallurgical By stopping the fiow of the current through the electrol zing tank during the be lessened, but this loss is more than compensated for-by the gain in physical and- 'metallurgic'al characteristics of the-copper deposit. Whenproceeding in such a manner I'obtain deposits of dense electrolytic copper, free from twinned crystals and amorphous deposits of cop er' or hydrogen.

I have found that goo results are obtained by using twenty cycles perv minute copper deposited will with an open circuit for substantially twenty per cent per cycle, so that the impressed current in any particular period of installation by means of whic my improved process may be carried out.

Fig. 2 represents a plan View of the mechanical switching device.

Like numerals in the respective figures represent like parts.

As shown in Fig. 1, the installation comprises an electrolytic tank T filled with an electrolyte E, preferably consisting of a copper sulfate solution. The said electrolytic'tank T is provided in the usual manner with an anode A and a cathode C. The anode A is connected to the positive pole of. a suitable electric generator G through the circuit line L.

A mechanical switching device in a tank 0 which is suitably filled with oil in order to reduce wear. This device may be in many forms, but a suitable current and switch device may consist of a sheet of metal 10 disposed in the shape of a circle, which has a portion removed as at 10 as shown. A rotating brush 11 mounted on the shaft 12 and revolved by means of the pulley 13, slides upon the said circular contact 10. n

The negative line wire L connects the cathode C with the rotating brush 11 and leads through L from the circular contact 10 back to the negative pole of the above mentioned electric generator G.

A condenser C and a resistance R bridge the switching device between the lines L and L as shown. It is desirable to mount a'plurality of brushes driven by a common shaft, and thus use a plurality of tanks through which the current is alternately S is located passed so that the load on the generator is more nearly constant.

It is thus evident that by varying the speed of the rotating brush 11, I am enabled to obtain any desired number of interruptions of the electrolyzing current.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. The process of electrolyzing cupriferous solutions which consists in carrying out the electrolysis 'incycles, the electrolyzing current being impressed during each cycle for a predetermined fraction thereof.

2. The process of electrolyzing cupriferous solutions which consists in carrying out the electrolysis in cycles, the electrolyggg current being impressed during each 0 cle for a predetermined fraction thereof during the submersion of the electrodes.

3. The process of electrolyzing cupriferous solutions which consists in carrying out the electrolysis in cycles, the electrolyzing current being impressed during each cycle for a predetermined fraction thereof, the impressed period being the longer.

4:. The process of electrolyzingmupriferous solutions which consists in carrying out the electrolysis by impressing the electrolyzing current periodically at predetermined intervals.

5. The process of electrolyzing copper sulfate solutions which consists incarrying out the'electrolysis in substantially twenty cycles per minute, the electrolyzing current being impressed during each cycle for substantially eighty per cent of the cycle period.

6. The process of electrolyzing cupriferous solutions which consists in carrying out the electrolysis by reversing the electrolyzing current periodically at predetermined intervals.

In witness whereof, I have hereunto set my hand at the borough of Manhattan, city and State of New York, this 10th day of January, 1922.

FRANK L. ANTISELL.- 

